The Tuck and Jerk is performed when the internet is down or porn is unavailable. In this situation the male party tucks his genitals between his legs to resemble the genitals of a woman. He then takes a picture of this and uses it to masturbate. In effect a person is creating their own porn to jerk it to.

I need to buy a playboy. Last night the modem when down, so I had to Tuck and Jerk.